Gas lift valve with mixed bellows and floating constant volume fluid chamber

ABSTRACT

A valve apparatus capable of withstanding high pressures and techniques for using this apparatus in various suitable applications are provided. The valve apparatus typically includes both an upper bellows comprising a standard, convoluted bellows and a lower bellows comprising an edge-welded bellows. The valve apparatus may also include a floating, constant volume fluid chamber that travels with the lower edge-welded bellows as the lower bellows compresses and expands in an effort to protect the lower bellows from very high internal volume fluid pressure.

CLAIM OF PRIORITY UNDER 35 U.S.C. 119

This application is a continuation of U.S. patent application Ser. No.14/021,326, filed Sep. 9, 2013 and entitled “Gas Lift Valve with MixedBellows and Floating Constant Volume Fluid Chamber,” which claimsbenefit of U.S. Provisional Patent Application No. 61/701,220, filedSep. 14, 2012 and sharing the same title, both of which are hereinincorporated by reference in their entireties.

BACKGROUND

Field

Embodiments of the present disclosure generally relate to valves capableof withstanding high pressures, including valves for use in hydrocarbonwells configured for artificial lift operations, for example.

Description of the Related Art

To obtain hydrocarbon fluids from an earth formation, a wellbore isdrilled into the earth to intersect an area of interest within aformation. The wellbore may then be “completed” by inserting casingwithin the wellbore and setting the casing therein using cement, forexample. In the alternative, the wellbore may remain uncased (an “openhole” wellbore), or may be only partially cased. Regardless of the formof the wellbore, production tubing is typically run into the wellboreprimarily to convey production fluid (e.g., hydrocarbon fluid, as wellas water and other, non-hydrocarbon gases) from the area of interestwithin the wellbore to the surface of the wellbore.

Often, pressure within the wellbore is insufficient to cause theproduction fluid to rise naturally through the production tubing to thesurface of the wellbore. Thus, to force the production fluid from thearea of interest within the wellbore to the surface, artificial liftmeans are sometimes employed. Gas lift and steam injection are examplesof artificial lift means for increasing production of oil and gas from awellbore.

Gas lift systems are often the preferred artificial lifting systemsbecause operation of gas lift systems involves fewer moving parts thanoperation of other types of artificial lift systems, such as sucker rodlift systems. Moreover, because no sucker rod is required to operate thegas lift system, gas lift systems are usable in offshore wells havingsubsurface safety valves that would interfere with a sucker rod.

Gas lift systems commonly incorporate one or more valves in side pocketmandrels of the production tubing to enable the lifting of productionfluid to the surface. Ideally, the gas lift valves allow gas from theannulus between the casing and production tubing to enter the tubingthrough the valves, but prevent reverse flow of production fluid fromthe tubing to the annulus.

SUMMARY

Embodiments of the present disclosure generally relate to a valveapparatus having two different bellows types and a floating constantvolume fluid chamber in which one of the bellows travels. In thismanner, the valve apparatus is capable of withstanding extremely highpressures (e.g., at least 10,000 psi).

One embodiment of the present invention is a valve for controlling fluidflow between an inlet and an outlet. The valve generally includes one ormore components forming a housing for the valve, a first bellows coupledto the housing, and a second bellows coupled to the housing, wherein thesecond bellows is a different bellows type than the first bellows.

Another embodiment of the present invention is a method for performingdownhole gas lift operations. The method generally includes providing avalve and opening the valve. The valve generally includes one or morecomponents forming a housing having an inlet and an outlet for fluidflow; a seating element disposed in the housing, wherein an orifice inthe seating element permits fluid flow between the inlet and the outlet;a stem configured to move in the housing, wherein a sealing elementassociated with the stem is configured to engage the orifice to preventthe fluid flow between the inlet and the outlet, thereby closing thevalve; a first bellows coupled to the housing and to the stem; and asecond bellows coupled to the housing and to a movable piston of avariable volume chamber in the housing, wherein the second bellows is adifferent bellows type than the first bellows. Opening the valvegenerally involves injecting gas downhole, wherein an injected gaspressure is greater than a dome gas pressure in the variable volumechamber, such that the stem moves away from the seating element to allowthe fluid flow between the inlet and the outlet via the orifice.

Yet another embodiment of the present invention is a system for downholegas lift operations. The system generally includes casing disposed in awellbore; production tubing disposed in the casing; and at least onevalve. The at least one valve generally includes one or more componentsforming a housing having an inlet and an outlet for fluid flow, whereinthe fluid flow enters the inlet from an annulus between the casing andthe production tubing and exits the outlet into the production tubing; afirst bellows coupled to the housing; and a second bellows coupled tothe housing, wherein the second bellows is a different bellows type thanthe first bellows. For some embodiments, the at least one valve isdisposed in a side pocket mandrel of the production tubing.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe various aspects, briefly summarized above, may be had by referenceto embodiments, some of which are illustrated in the appended drawings.It is to be noted, however, that the appended drawings illustrate onlytypical embodiments of this disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective embodiments.

FIG. 1 is a cross-sectional view of a gas injection wellbore, inaccordance with an embodiment of the present disclosure.

FIG. 2 is a cross-sectional view of a side pocket mandrel incorporatinga gas lift valve, in accordance with an embodiment of the presentdisclosure.

FIG. 3 is a cross-sectional view of a valve apparatus, in accordancewith an embodiment of the present disclosure.

FIG. 4A is a cross-sectional view of an upper portion of the valveapparatus in FIG. 3, zoomed in to show a pressurized dome and upper,convoluted bellows when the valve apparatus is closed, in accordancewith an embodiment of the present disclosure.

FIG. 4B is a cross-sectional view of the upper portion of the valveapparatus in FIG. 3, when the valve apparatus is open, in accordancewith an embodiment of the present disclosure.

FIG. 5 is a cross-sectional view of a lower portion of the valveapparatus in FIG. 3, in accordance with an embodiment of the presentdisclosure.

FIG. 6A is a cross-sectional view of the valve apparatus in FIG. 3,zoomed in to show a shaft, a sliding cylinder, and lower, edge-weldedbellows when the valve apparatus is closed, in accordance with anembodiment of the present disclosure.

FIG. 6B is a cross-sectional view of the valve apparatus in FIG. 3,zoomed in to show the shaft, the sliding cylinder, and the lower,edge-welded bellows when the valve apparatus is open, in accordance withan embodiment of the present disclosure.

FIG. 7 is a flow diagram of example operations for performing downholegas lift, in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

Embodiments of the present disclosure provide a valve apparatus capableof withstanding high pressures and techniques for using the valveapparatus in various suitable applications. The valve apparatustypically includes both an upper bellows comprising a standard,convoluted bellows and a lower bellows comprising an edge-weldedbellows. The valve apparatus may also include a floating, constantvolume fluid chamber that travels with the lower edge-welded bellows asthe lower bellows compresses and expands in an effort to protect thelower bellows from very high internal volume fluid pressure.

FIG. 1 illustrates a typical gas lift completion for hydrocarbonrecovery, which may include a wellhead 112 atop a casing 114 that passesthrough a formation 102. Production tubing 120 positioned in the casing114 may have a number of side pocket mandrels 130 and a productionpacker 122. To conduct a gas lift operation, operators conventionallyinstall gas lift valves 140 in the side pocket mandrels 130.

With the valves 140 installed, compressed gas G from the wellhead 112may be injected into the annulus 116 between the production tubing 120and the casing 114. In the side pocket mandrels 130, the gas lift valves140 then act as one-way valves by opening in the presence ofhigh-pressure injection gas, thereby allowing the gas to flow from theannulus 116 to the tubing 120. When pressure is reduced as a result ofdiscontinued pumping of gas at the surface, the valve 140 closes toprevent reverse production fluid flow from the tubing 120 to the annulus116.

Downhole, the production packer 122 forces upwards travel through theproduction tubing 120 of production fluid P entering casing perforations115 from the formation 102. Additionally, the packer 122 keeps the gasflow in the annulus 116 from entering the tubing 120.

The injected gas G passes down the annulus 116 until it reaches the sidepocket mandrels 130. Entering the mandrel's inlet ports 135, the gas Gfirst passes through the gas lift valve 140 before it can pass into theproduction tubing 120. Once in the tubing 120, the gas G can then riseto the surface, lifting production fluid P in the production tubing inthe process.

FIG. 2 depicts an example disposition of a gas lift valve (e.g., valveapparatus 300 of the present disclosure) in a side pocket mandrel 130.As depicted, one or more entrance ports 302 (i.e., inlets) of the gaslift valve may be placed adjacent a mandrel port 135 such thatpressurized injection gas may enter the valve from the annulus 116 andflow through the valve into the production tubing 120 via an exit port304 (i.e., an outlet). Packing seals 202, 204 may be used between thegas lift valve and the walls of the side pocket mandrel 130 on eitherside of the entrance port 302 and the mandrel port 135 to control theflow of injection gas.

There is demand in the hydrocarbon recovery industry for gas lift valvesfor high gas pressure applications. Existing gas lift valves usuallywork up to 2500 psi injection pressure, but desired operating pressuresrange up to 10,000 psi and beyond. Currently there is no valve on themarket that can work at such high pressures. Accordingly, what is neededis a valve apparatus for withstanding such high pressures.

The problem with current gas lift valves may be attributed to a sealthat separates the valve dome's nitrogen pressure and the injection gaspressure. This seal is typically a bellows that may have a standardconvoluted or edge-welded configuration. Single or multiple bellows maybe used for this purpose and may be arranged in differentconfigurations. The bellows may be surrounded or filled withnon-compressible fluid (e.g., silicone oil) to prevent the bellows fromdamage caused by over-compression by gas. However, a gas lift valvebellows is not pressure balanced until exposed to injection pressurethat usually acts on the bellows' external surface, whereas the domepressure acts on the bellows' internal surface. This principle can beinverted, as well, such that the dome pressure acts on the bellows'external surface and the injection pressure acts inside the bellows.

The bellows assembly may be arranged, for example, as described in U.S.Pat. Nos. 2,880,620 and 5,662,335, in which two appropriately connectedbellows of different diameters are used to maintain a constant volume ofa non-compressible compressible fluid that prevents bellows damage. U.S.Pat. No. 2,880,620 describes standard convoluted bellows, while U.S.Pat. No. 5,662,335 describes two edge-welded bellows. The volume betweenthe valve housing and the bellows' outer diameter (OD) is filled with aconstant volume of non-compressible fluid. When injection fluid isapplied to the volume between the valve's inner diameter (ID) and thebellows' outside surface, the bellows exposed to highproduction/injection fluid pressure cannot be damaged since thedifferential pressure across the bellows is working against thenon-compressible fluid inside the bellows (see, e.g., FIG. 4 in U.S.Pat. No. 5,662,335).

This principle will work as long as the dimensional difference betweenbellows elements, such as the bellows elements' thickness, can withstandthe differential pressure. Once the weakest bellows element yields andis exposed to the differential pressure, the bellows will fail. Tovisualize this, imagine a thin balloon-like container having a uniformwall thickness filled with water and uniformly exposed to externalpressure. Theoretically, external gas pressure can be infinitely highsince the pressure is working against non-compressible water. However,the wall thickness is never perfectly uniform, and at a certain gaspressure, the thinnest section of the wall will yield. The sameprinciple pertains to bellows elements, which will eventually yield dueto this principle of non-uniform element thickness.

The main advantage of edge-welded bellows in this principle is notutilized: edge-welded bellows can be completely compressed to a solidstate by external pressure in an effort to prevent bellows deformationand failure. When fully compressed, edge-welded bellows elements arebutted against each other and mating parts to which the individualbellows elements are welded; hence, deformation cannot take place. Fullcompression prevents the edge-welded bellows from yielding. As of thetime embodiments of the present disclosure were conceived, a gas liftvalve utilizing fully compressed edge-welded bellows did not exist onthe market.

Furthermore, there is currently no bellows application wherenon-compressible fluid is applied to both the internal and externalbellows surfaces to prevent the bellows from damage. Embodiments of thepresent disclosure take advantage of the recognition that when thebellows is either compressing or expanding, fluid inside and outside thebellows may have constant volume in order to accept the pressure load:if pressure is applied from outside of the bellows, internally trappedfluid will prevent the bellows from collapsing and if pressure isapplied from inside the bellows, externally trapped fluid will preventthe bellows from bursting.

In order to achieve this, embodiments of the present disclosure use twodifferent types of bellows (e.g., one standard convoluted bellows andone edge-welded bellows). For the description that follows, FIG. 3 is across-sectional view of a valve 300, in accordance with an embodiment ofthe present disclosure. FIGS. 4A and 4B illustrate an upper portion 306of the valve 300, whereas FIG. 5 illustrates a lower portion 308 of thevalve. FIGS. 6A and 6B illustrate a fraction 310 of the lower portion308 of the valve 300, zoomed in to show the movable components.

As illustrated in FIG. 4A, the upper bellows 316 (which may be astandard convoluted bellows) may be mechanically coupled (e.g., welded)to a central adapter 314 at one end. The other end of the upper bellows316 may be welded (or suitably coupled in another manner) to a piston318. The upper bellows 316 is referred to as the “upper” bellows sincegas lift valves are usually installed in a vertical position, and thisbellows 316 is in the upper portion 306 of the valve 300 when installed.The upper bellows 316 is installed inside a valve body 312, which may becharged with a suitable gas, such as nitrogen, to a predeterminedpressure. This gas may enter the dome volume 320 through drill corevalve 322. Using a standard convoluted bellows for the upper bellows 316(as compared to edge-welded bellows, for example) may allow much lowerdome pressure, thereby providing increased upper bellows performance andlower overall stress level and enhancing the life expectancy and cyclenumber of the bellows.

As illustrated in FIG. 5, the lower bellows 332 (which may be anedge-welded bellows (EWB)) may be mechanically coupled (e.g., welded) toa hollow shaft 330 at one end, and the other end of the bellows 332 maybe welded (or suitably coupled in another manner) to a stem 334. Asliding cylinder 342 may be installed over the shaft 330 with a(pre-installed) seal 344 (e.g., an O-ring). The sliding cylinder 342 maybe threaded for coupling with the stem 334, and/or the stem 334 may bewelded to the sliding cylinder at welding points 356 for someembodiments. Non-compressible fluid (e.g., silicone oil) may be added tovolume 352 through ports 357, where volume 352 is the volume outside thelower bellows' outer diameter (OD) and the inner diameter (ID) of thesliding cylinder 342, as illustrated in FIG. 6A. All remaining air maymost likely be completely evacuated from volume 352. Once thenon-compressible fluid has filled the volume 352, plugs 358 may beinstalled in the ports 357.

At this point, the lower bellows 332 is stretched to its free length(i.e., uncompressed). With this design, the lower bellows 332 is fullyprotected from debris or chemical impact since this bellows isencapsulated inside the sliding cylinder 342 by the stem 334. Thesubassembly composed of the shaft 330, the seal 344, the lower bellows332, the sliding cylinder 342, the stem 334, and the tungsten carbide(WC) ball 336 coupled thereto may then be inserted through the centraladapter 314 and seal tightened with two nuts 346, for example, as shownin FIG. 5.

Volume 326 may then be filled with a non-compressible fluid (e.g.,silicone oil) via port 328 in the central adapter 314, as depicted inFIG. 4A. All air may most likely be completely evacuated using a vacuumor any other suitable means, and plugs for ports 324 and 328 areinstalled.

A nitrogen charge is applied to the valve dome volume 320 (i.e.,variable volume chamber). This dome pressure will partially compressupper bellows 316, as shown in FIG. 4A, such that the non-compressiblefluid (e.g., silicone oil) will flow via volume 326 and duct 350 to theinside of the lower bellows 332, thereby expanding the lower bellows.With this expansion of the lower bellows 332, the stem 334 will movedown, and the valve 300 will close by engaging the orifice 338 in theseating element 340 with the WC ball 336, as portrayed in FIG. 6A. Thiscontact of the WC ball 336 actually functions as a mechanical stop forthe upper bellows 316, where the mechanical stop prevents the upperbellows from over-compressing. At this point, the valve 300 is now inthe closed position, and no injection gas can flow through the orifice338 to the exit port 304.

When injection gas is applied through the entrance ports 302, theresulting pressure will at a certain point start compressing the lowerbellows 332, and the non-compressible fluid (e.g., silicone oil) willflow from the lower bellows 332 to the upper bellows 316 via the duct350 and the volume 326, thereby expanding the upper bellows and raisingthe piston 318, as illustrated in FIG. 4B. As the lower bellows 332 iscompressed, the sliding cylinder 342, the stem 334, and the WC ball 336move up and away from the orifice 338, thereby opening the valve 300, asdepicted in FIG. 6B. At a certain high pressure, the lower bellows 332will be fully compressed to solid and will be capable of withstandingextremely high injection pressures (e.g., of at least 10,000 psi or11,000 psi) since the fully compressed lower bellows is now virtually asolid piece of metal. Once the lower bellows 332 is fully compressed,injection pressure will have no impact on the upper bellows 316.

A floating, constant volume is maintained inside the sliding cylinder342. When the lower bellows 332 begins to compress due to the injectionpressure, the non-compressible fluid will start displacing from thevolume 352 to volume 354 created by movement of the sliding cylinder 342along the shaft 330. The seal 344 slides along the shaft 330 creatingthis expanding volume 354 (and contracting volume 352), as illustratedin FIG. 6B. This floating constant volume feature is accomplished usingthe sliding cylinder 342 and the seal 344. Volumetric displacementduring axial travel of the lower bellows 332 is exactly the same forvolumes 352 and 354 per unit of the lower bellows' travel, either tocompression or expansion. This is achieved by exact volumetriccalculation and associated component design and is desired to obtainsignificantly increased bellows protection from internal or externalpressure.

As an example of such component design, the outer diameter of the shaft330 may be designed and fabricated such that as the lower bellows 332 iscompressed and the non-compressible fluid is displaced, the volumeexpansion in volume 354 (between the OD of the shaft 330 and the ID ofthe sliding cylinder 342) is the same as the volume contraction involume 352 (between the OD of the lower bellows 332 and the ID of thesliding cylinder 342). In other words, the outer diameter of the shaft330 is harmonized with the inner diameter of the sliding cylinder 342and the outer diameter of the lower bellows 332 in an effort to producethis equivalent volumetric displacement.

After application of the injection gas, the lower bellows 332 will befully compressed to solid, which is desired to provide ultimate bellowsprotection from over-pressurizing and prevent deformation and failure ofthe lower bellows. As the lower bellows 332 is compressed, thenon-compressible fluid contained inside the bellows system will travelfrom inside the lower bellows 332 to the inner diameter of the upperbellows 316, thereby expanding the upper bellows 316 and elevating thepiston 318, as shown in FIG. 4B. As this occurs, the sliding cylinder342, the stem 334, and the WC ball 336 move up and away from the orifice338, as depicted in FIG. 6B. The valve 300 is now open for flow ofinjection fluid for artificial lift operations.

When the valve 300 is utilized for gas lift operations, the valveprovides injection pressure amplification. In other words, since theupper bellows 316 is much larger than the lower bellows 332, in order toopen the valve 300 for flow, a much higher injection pressure isinvolved due to the difference in cross-sectional area of the upperbellows 316 versus the outer diameter (OD) of the shaft 330.

The arrangement of the valve 300 described above is shown for gas liftapplications. However, this seal arrangement utilizing two differentbellows types and a floating constant volume fluid chamber may be usedfor other applications, such as gate valves shaft sealing, pumps shaftssealing, and the like.

FIG. 7 is a flow diagram of example operations 700 for performingdownhole gas lift, in accordance with embodiments of the presentdisclosure. The operations 700 may begin, at 702, by providing a valve.The valve generally includes one or more components forming a housinghaving an inlet and an outlet for fluid flow; a seating element disposedin the housing, wherein an orifice in the seating element permits fluidflow between the inlet and the outlet; a stem configured to move in thehousing, wherein a sealing element associated with the stem isconfigured to engage the orifice to prevent the fluid flow between theinlet and the outlet, thereby closing the valve; a first bellows (e.g.,lower bellows 332) coupled to the housing and to the stem; and a secondbellows (e.g., upper bellows 316) coupled to the housing and to amovable piston of a variable volume chamber in the housing. The secondbellows is a different bellows type than the first bellows. For example,the first bellows may be an edge-welded bellows, and the second bellowsmay be a standard convoluted bellows. For some embodiments, the sealingelement is a tungsten carbide (WC) ball disposed at a tip of the stem.

At 704, the valve may be opened by injecting gas downhole. A pressure ofthe injected gas (i.e., an injected gas pressure) may be greater than adome gas pressure in the variable volume chamber, such that the firstbellows is compressed and the stem moves away from the seating elementto allow the fluid flow between the inlet and the outlet via theorifice. Injecting the gas downhole at 704 fully compresses the firstbellows to solid.

At 706, the operations 700 may further include closing the valve bydiscontinuing to inject the gas downhole. Without the injected gas, thedome gas pressure may be greater than an external gas pressure externalto the housing, such that the stem moves and the sealing element engagesthe orifice in the seating element.

According to some embodiments of the present disclosure, the valve mayinclude a shaft coupled to the housing at a first end of the shaft. Thefirst bellows may be coupled to the stem and to a second end of theshaft, such that compression of the first bellows causes the stem tomove towards the shaft and expansion of the first bellows causes thestem to move away from the shaft. The valve may also include a slidingcylinder containing the first bellows, coupled to the stem, andsealingly engaged to the second end of the shaft. For some embodiments,a first volume between an inner diameter of the sliding cylinder and anouter diameter of the first bellows is filled with a firstnon-compressible fluid. For some embodiments, axial travel of thesliding cylinder relative to the shaft causes equal volumetricdisplacement of the first non-compressible fluid between an upperportion (e.g., volume 354) of the first volume above the second end ofthe shaft and a lower portion (e.g., volume 352) of the first volumebelow the second end of the shaft. For some embodiments, a second volumeformed by an inner diameter of the first bellows, an inner diameter ofthe second bellows, a duct of the shaft, and a hollow portion of thehousing is filled with a second non-compressible fluid that is displacedas the first and second bellows are compressed or expanded. The firstand/or the second non-compressible fluid may be silicone oil, forexample.

CONCLUSION

Embodiments of the present disclosure provide a valve apparatus havingtwo different bellows types and a floating constant volume fluid chamberin which one of the bellows travels. In this manner, the valve apparatusis capable of withstanding extremely high pressures (e.g., at least10,000 psi).

While the foregoing is directed to embodiments of the presentdisclosure, other and further embodiments may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

1. A valve for controlling fluid flow between an inlet and an outlet,comprising: one or more components forming a housing for the valve; abellows coupled to the housing; a stem configured to move in thehousing; a shaft coupled to the housing, wherein the bellows is coupledto the stem and to the shaft, such that compression of the bellowscauses the stem to move towards the shaft and expansion of the bellowscauses the stem to move away from the shaft; and a sliding cylindercontaining the bellows, coupled to the stem, and configured to movealong the shaft.
 2. The valve of claim 1, wherein the bellows comprisesan edge-welded bellows.
 3. The valve of claim 1, further comprising: aseating element disposed in the housing, wherein an orifice in theseating element permits the fluid flow between the inlet and the outletand wherein a sealing element associated with the stem is configured tomate with the orifice to prevent the fluid flow between the inlet andthe outlet, thereby closing the valve.
 4. The valve of claim 3, whereinthe bellows is coupled to the housing and to the stem.
 5. The valve ofclaim 3, wherein the bellows is fully compressed to solid when the valveis open.
 6. The valve of claim 3, wherein the sealing element comprisesa tungsten carbide (WC) ball disposed at a tip of the stem.
 7. The valveof claim 3, wherein: the shaft is coupled to the housing at a first endof the shaft; the bellows is coupled to the stem and to a second end ofthe shaft; and the sliding cylinder containing the bellows, coupled tothe stem, is sealingly engaged to the second end of the shaft.
 8. Thevalve of claim 7, wherein a first volume between an inner diameter ofthe sliding cylinder and an outer diameter of the bellows is filled witha first non-compressible fluid.
 9. The valve of claim 8, wherein thefirst non-compressible fluid comprises silicone oil.
 10. The valve ofclaim 8, wherein axial travel of the sliding cylinder relative to theshaft causes equal volumetric displacement of the first non-compressiblefluid between an upper portion of the first volume above the second endof the shaft and a lower portion of the first volume below the secondend of the shaft.
 11. The valve of claim 8, wherein a second volumeformed at least in part by an inner diameter of the bellows, a duct ofthe shaft, and a hollow portion of the housing is filled with a secondnon-compressible fluid that is displaced as the bellows is compressed orexpanded.
 12. The valve of claim 3, further comprising another bellowscoupled to the housing and to a movable piston of a variable volumechamber in the housing, wherein the other bellows is compressed when thevalve is closed.
 13. The valve of claim 1, wherein the valve isconfigured to operate in external pressures of at least 10,000 psi. 14.A method for performing downhole gas lift operations, comprising:providing a valve, comprising: one or more components forming a housinghaving an inlet and an outlet for fluid flow; a seating element disposedin the housing, wherein an orifice in the seating element permits fluidflow between the inlet and the outlet; a stem configured to move in thehousing, wherein a sealing element associated with the stem isconfigured to engage the orifice to prevent the fluid flow between theinlet and the outlet, thereby closing the valve; a bellows coupled tothe housing and to the stem; a shaft coupled to the housing, wherein thebellows is coupled to the stem and to the shaft, such that compressionof the bellows causes the stem to move towards the shaft and expansionof the bellows causes the stem to move away from the shaft; and asliding cylinder containing the bellows, coupled to the stem, andconfigured to move along the shaft; and opening the valve by injectinggas downhole, wherein an injected gas pressure is greater than a domegas pressure in a variable volume chamber in the housing, such that thestem moves away from the seating element to allow the fluid flow betweenthe inlet and the outlet via the orifice.
 15. The method of claim 14,further comprising closing the valve by discontinuing to inject the gasdownhole, wherein the dome gas pressure is greater than an external gaspressure external to the housing such that the stem moves and thesealing element engages the orifice in the seating element.
 16. Themethod of claim 14, wherein injecting the gas downhole fully compressesthe bellows to solid.
 17. The method of claim 14, wherein: the shaft iscoupled to the housing at a first end of the shaft; the bellows iscoupled to the stem and to a second end of the shaft; and the slidingcylinder containing the bellows, coupled to the stem, is sealinglyengaged to the second end of the shaft.
 18. The method of claim 17,wherein a first volume between an inner diameter of the sliding cylinderand an outer diameter of the bellows is filled with a firstnon-compressible fluid.
 19. The method of claim 18, wherein axial travelof the sliding cylinder relative to the shaft causes equal volumetricdisplacement of the first non-compressible fluid between an upperportion of the first volume above the second end of the shaft and alower portion of the first volume below the second end of the shaft. 20.The method of claim 18, wherein a second volume formed at least in partby an inner diameter of the bellows, a duct of the shaft, and a hollowportion of the housing is filled with a second non-compressible fluidthat is displaced as the bellows is compressed or expanded.